"Descendants" actor Cameron Boyce was just 20 years old when he suddenly passed away in July 2019. With Mother's Day just days away, his mom, Libby Boyce, opened up in a new essay about how she's dealt with the grief surrounding his death.

Cameron's cause of death was Sudden Unexpected Death in Epilepsy (SUDEP). Cameron had been diagnosed with epilepsy prior to his death, but the mother revealed she had "never heard of" SUDEP until it took her son's life.

In the last 10 months, Libby revealed she's been in touch with mothers across the country who've faced similar tragedies. In an essay for "Good Morning America," the heartbroken mom shared that she will not let her son die in vain. Rather, she vows to bring awareness to the condition that took her son's life.

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Actor Cameron Boyce attends Nickelodeon's 2016 Kids' Choice Awards at The Forum on March 12, 2016 in Inglewood, Calif. (Getty)

"I intend to use my voice on behalf of these moms to bring a face to this tragic issue and to bring attention to epilepsy; the most common disease that we know the least about," Libby writes.

Cameron's mom recalled the late Disney star's "authentic" and "genuine" spirit, noting that she had an especially close bond with her son.

"He once told me that he couldn't wait for me to be older, so that he could take care of me," she explains.

She called the 10 months since Cameron's passing "life-changing," as she now lives with a "gaping hole that is raw and gut-wrenching."

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Cameron Boyce poses with Adam Sandler at the 2017 Radio Disney Music Awards. Sandler, who starred as Boyce's father in "Grown Ups" and "Grown Ups 2," honored the late star with donations to The Thirst Project. (Getty)

What's brought her some comfort, though, is connecting with other moms whose children also passed away from SUDEP.

"For this Mother’s Day, I want to pay tribute to all of the SUDEP mom warriors who live with this horrific burden. Together, we will fight for more awareness, better understanding of the various types of epilepsy and appropriate treatments to address each type and for a cure for epilepsy and SUDEP," Libby writes.

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More information about Libby's efforts can be found at the Cameron Boyce Foundation website.